Workplace physical activity practices in real life: a scoping review of grey literature for small- and medium-sized enterprises.

BACKGROUND: There is a need to scale-up effective physical activity (PA) programmes for small- and medium-sized enterprises (SMEs), where the uptake of PA interventions is low. Identifying real-life workplace practices in PA could contribute to a better understanding of what PA programmes might be most grounded in the 'real world'. However, there is a scarcity of evidence showing what gets done. This study aimed to identify, describe and comprehensively summarize the real-life implementations of workplace PA initiatives, particularly in Europe, as a prior step to disseminating future feasible PA practices for SMEs. METHODS: A scoping review of grey literature included a systematic search in the Google advanced search platform that permuted a combination of key concepts (PA, workplace, interventions/programmes), internet domains, and search operators in six different languages (Catalan, Finnish, French, Dutch, English and Spanish) between 2015 and November 2020. The analysis process was iterative, and multiple methods were used to sort, group and categorize the initiatives. RESULTS: There were a total of 713 real-life workplace PA initiatives from different-sized organizations identified. These were categorized into five themes: active work and living, exercise and fitness programs, management and leadership, communication and dissemination, and facilities. Finally, feature trees showing a menu for real-life workplace PA practices were implemented. CONCLUSIONS: Identifying real-life practice providing a state-of-the-art snapshot of current PA practices in workplaces, which is a starting point to better understand feasible practices in the context of small- and medium-sized workplaces.

Prunus persica plant endogenous peptides PpPep1 and PpPep2 cause PTI-like transcriptome reprogramming in peach and enhance resistance to Xanthomonas arboricola pv. pruni.

BACKGROUND: Rosaceae species are economically highly relevant crops. Their cultivation systems are constrained by phytopathogens causing severe losses. Plants respond to invading pathogens through signaling mechanisms, a component of which are of them being plant elicitor peptides (Peps). Exogenous application of Peps activates defense mechanisms and reduces the symptoms of pathogen infection in various pathosystems. We have previously identified the Rosaceae Peps and showed, in an ex vivo system, that their topical application efficiently enhanced resistance to the bacterial pathogen Xanthomonas arboricola pv. pruni (Xap). RESULTS: Here we demonstrate the effectiveness of Prunus persica peptides PpPep1 and PpPep2 in protecting peach plants in vivo at nanomolar doses, with 40% reduction of the symptoms following Xap massive infection. We used deep sequencing to characterize the transcriptomic response of peach plants to preventive treatment with PpPep1 and PpPep2. The two peptides induced highly similar massive transcriptomic reprogramming in the plant. One hour, 1 day and 2 days after peptide application there were changes in expression in up to 8% of peach genes. We visualized the transcriptomics dynamics in a background knowledge network and detected the minor variations between plant responses to PpPep1 and PpPep2, which might explain their slightly different protective effects. By designing a P. persica Pep background knowledge network, comparison of our data and previously published immune response datasets was possible. CONCLUSIONS: Topical application of P. persica Peps mimics the PTI natural response and protects plants against massive Xap infection. This makes them good candidates for deployment of natural, targeted and environmental-friendly strategies to enhance resistance in Prunus species and prevent important biotic diseases.

Correction to: Lack of adverse effects in subchronic and chronic toxicity/carcinogenicity studies on the glyphosate-resistant genetically modified maize NK603 in Wistar Han RCC rats.

In the original publication, the starting point in time for the three feeding trials.

Lack of adverse effects in subchronic and chronic toxicity/carcinogenicity studies on the glyphosate-resistant genetically modified maize NK603 in Wistar Han RCC rats.

In 2012, a controversial study on the long-term toxicity of a Roundup herbicide and the glyphosate-tolerant genetically modified (GM) maize NK603 was published. The EC-funded G-TwYST research consortium tested the potential subchronic and chronic toxicity as well as the carcinogenicity of the glyphosate-resistant genetically modified maize NK603 by performing two 90-day feeding trials, one with GM maize inclusion rates of 11 and 33% and one with inclusion rates of up to 50%, as well as a 2-year feeding trial with inclusion rates of 11 and 33% in male and female Wistar Han RCC rats by taking into account OECD Guidelines for the testing of chemicals and EFSA recommendations on the safety testing of whole-food/feed in laboratory animals. In all three trials, the NK603 maize, untreated and treated once with Roundup during its cultivation, and the conventional counterpart were tested. Differences between each test group and the control group were evaluated. Equivalence was assessed by comparing the observed difference to differences between non-GM reference groups in previous studies. In case of significant differences, whether the effects were dose-related and/or accompanied by changes in related parameters including histopathological findings was evaluated. It is concluded that no adverse effects related to the feeding of the NK603 maize cultivated with or without Roundup for up to 2 years were observed. Based on the outcome of the subchronic and combined chronic toxicity/carcinogenicity studies, recommendations on the scientific justification and added value of long-term feeding trials in the GM plant risk assessment process are presented.

Diversity of plant defense elicitor peptides within the Rosaceae.

BACKGROUND: Plant elicitor peptides (Peps) are endogenous molecules that induce and amplify the first line of inducible plant defense, known as pattern-triggered immunity, contributing to protect plants against attack by bacteria, fungi and herbivores. Pep topic application and transgenic expression have been found to enhance disease resistance in a small number of model plant-pathogen systems. The action of Peps relies on perception by specific receptors, so displaying a family-specific activity. Recently, the presence and activity of Peps within the Rosaceae has been demonstrated. Here we characterized the population of Pep sequences within the economically important plant family of Rosaceae, with special emphasis on the Amygdaleae and Pyreae tribes, which include the most relevant edible species such as apple, pear and peach, and numerous ornamental and wild species (e.g. photinia, firethorn and hawthorn). RESULTS: The systematic experimental search for Pep and the corresponding precursor PROPEP sequences within 36 Amygdaleae and Pyreae species, and 100 cultivars had a highly homogeneous pattern, with two tribe-specific Pep types per plant, i.e. Pep1 and Pep2 (Amygdaleae) or Pep3 and Pep4 (Pyreae). Pep2 and Pep3 are highly conserved, reaching identity percentages similar to those of genes used in plant phylogenetic analyses, while Pep1 and Pep4 are somewhat more variable, with similar values to the corresponding PROPEPs. In contrast to Pep3 and Pep4, Pep1 and Pep2 sequences of different species paralleled their phylogenetic relationships, and putative ancestor sequences were identified. The large amount of sequences allowed refining of a C-terminal consensus sequence that would support the protective activity of Pep1-4 in a Prunus spp. and Xanthomonas arboricola pv. pruni system. Moreover, tribe-specific consensus sequences were deduced at the center and C-terminal regions of Peps, which might explain the higher protection efficiencies described upon topic treatments with Peps from the same tribe. CONCLUSIONS: The present study substantially enhances the knowledge on Peps within the Amygdaleae and Pyreae species. It can be the basis to design and fine-tune new control tools against important plant pathogens affecting Prunus, Pyrus and Malus species.

High CO2 concentration as an inductor agent to drive production of recombinant phytotoxic antimicrobial peptides in plant biofactories.

Cationic α-helical antimicrobial peptides such as BP100 are of increasing interest for developing novel phytosanitary or therapeutic agents and products with industrial applications. Biotechnological production of these peptides in plants can be severely impaired due to the toxicity exerted on the host by high-level expression. This can be overcome by using inducible promoters with extremely low activity throughout plant development, although the yields are limited. We examined the use of modified atmospheres using the increased levels of [CO2], commonly used in the food industry, as the inductor agent to biotechnologically produce phytotoxic compounds with higher yields. Here we show that 30% [CO2] triggered a profound transcriptional response in rice leaves, including a change in the energy provision from photosynthesis to glycolysis, and the activation of stress defense mechanisms. Five genes with central roles in up-regulated pathways were initially selected and their promoters successfully used to drive the expression of phytotoxic BP100 in genetically modified (GM) rice. GM plants had a normal phenotype on development and seed production in non-induction conditions. Treatment with 30 % [CO2] led to recombinant peptide accumulation of up to 1 % total soluble protein when the Os.hb2 promoter was used. This is within the range of biotechnological production of other peptides in plants. Using BP100 as a proof-of-concept we demonstrate that very high [CO2] can be considered an economically viable strategy to drive production of recombinant phytotoxic antimicrobial peptides in plant biofactories.

The production of recombinant cationic α-helical antimicrobial peptides in plant cells induces the formation of protein bodies derived from the endoplasmic reticulum.

Synthetic linear antimicrobial peptides with cationic α-helical structures, such as BP100, are valuable as novel therapeutics and preservatives. However, they tend to be toxic when expressed at high levels as recombinant peptides in plants, and they can be difficult to detect and isolate from complex plant tissues because they are strongly cationic and display low extinction coefficient and extremely limited immunogenicity. We therefore expressed BP100 with a C-terminal tag which preserved its antimicrobial activity and demonstrated significant accumulation in plant cells. We used a fluorescent tag to trace BP100 following transiently expression in Nicotiana benthamiana leaves and showed that it accumulated in large vesicles derived from the endoplasmic reticulum (ER) along with typical ER luminal proteins. Interestingly, the formation of these vesicles was induced by BP100. Similar vesicles formed in stably transformed Arabidopsis thaliana seedlings, but the recombinant peptide was toxic to the host during latter developmental stages. This was avoided by selecting active BP100 derivatives based on their low haemolytic activity even though the selected peptides remained toxic to plant cells when applied exogenously at high doses. Using this strategy, we generated transgenic rice lines producing active BP100 derivatives with a yield of up to 0.5% total soluble protein.

Constitutive expression of transgenes encoding derivatives of the synthetic antimicrobial peptide BP100: impact on rice host plant fitness.

BACKGROUND: The Biopeptide BP100 is a synthetic and strongly cationic α-helical undecapeptide with high, specific antibacterial activity against economically important plant-pathogenic bacteria, and very low toxicity. It was selected from a library of synthetic peptides, along with other peptides with activities against relevant bacterial and fungal species. Expression of the BP100 series of peptides in plants is of major interest to establish disease-resistant plants and facilitate molecular farming. Specific challenges were the small length, peptide degradation by plant proteases and toxicity to the host plant. Here we approached the expression of the BP100 peptide series in plants using BP100 as a proof-of-concept. RESULTS: Our design considered up to three tandemly arranged BP100 units and peptide accumulation in the endoplasmic reticulum (ER), analyzing five BP100 derivatives. The ER retention sequence did not reduce the antimicrobial activity of chemically synthesized BP100 derivatives, making this strategy possible. Transformation with sequences encoding BP100 derivatives (bp100der) was over ten-fold less efficient than that of the hygromycin phosphotransferase (hptII) transgene. The BP100 direct tandems did not show higher antimicrobial activity than BP100, and genetically modified (GM) plants constitutively expressing them were not viable. In contrast, inverted repeats of BP100, whether or not elongated with a portion of a natural antimicrobial peptide (AMP), had higher antimicrobial activity, and fertile GM rice lines constitutively expressing bp100der were produced. These GM lines had increased resistance to the pathogens Dickeya chrysanthemi and Fusarium verticillioides, and tolerance to oxidative stress, with agronomic performance comparable to untransformed lines. CONCLUSIONS: Constitutive expression of transgenes encoding short cationic α-helical synthetic peptides can have a strong negative impact on rice fitness. However, GM plants expressing, for example, BP100 based on inverted repeats, have adequate agronomic performance and resistant phenotypes as a result of a complex equilibrium between bp100der toxicity to plant cells, antimicrobial activity and transgene-derived plant stress response. It is likely that these results can be extended to other peptides with similar characteristics.

Use of the Superblock model for promoting physical activity in Barcelona: a one-year observational comparative study.

BACKGROUND: The Barcelona Superblock model transforms urban public spaces into active-friendly spaces, a key issue for public health. This study assessed the extent to which a newly developed Superblock in St. Antoni Market Square was used by citizens to perform physical activities and for sedentary behaviour during the first year of implementation. It then compared this citizens' use of the Superblock for physical activities and sedentary behaviour with a comparison site at one-year follow-up, when the Superblock was fully integrated into citizens' daily life. METHODS: This observational comparative study (May 2018-May 2019) used the System for Observing Play and Recreation in Communities (SOPARC). SOPARC assessed citizens' sitting, standing, walking, practice of vigorous activities and use of electric scooter by gender, age group and time of the day. At the Superblock site, two observers completed five weekly observations: the opening week, and at three, five, eight and twelve months. At the comparison site, observers completed one weekly observation at twelve months after the implementation of the Superblock. Observations included 4 days/week (including weekends) and, 4 h/day (morning, midday, afternoon, evening). RESULTS: At baseline, an average of 2,340 citizens/hour were observed using the Superblock but visits reduced by 12% in the next three observation weeks and 17.6% after one-year (mainly elderly and teenagers). At baseline, 92.9% walked in the Superblock, while 3.1% engaged in vigorous physical activity. After one year, citizens' walking decreased by 18.2%, from 2,170 citizens/hour at baseline to 1,930 citizens/hour. Citizens' engagement in vigorous activities also declined by 11%, from 73 citizens/hour at baseline to 65 citizens/hour at one-year follow up. In the comparison site, citizens' usage for walking and vigorous physical activity was similar to the Superblock. CONCLUSIONS: This is the first study to assess the extent to which citizens made use of the Barcelona Superblock model to perform physical activities, an urban built-environment intervention that is both novel and health-enhancing. The Superblock model would benefit from strategies maximizing effectiveness for promoting superblock-based physical activity, with special focus on seniors and teenagers.

Only half the transcriptomic differences between resistant genetically modified and conventional rice are associated with the transgene.

Besides the intended effects that give a genetically modified (GM) plant the desired trait, unintended differences between GM and non-GM comparable plants may also occur. Profiling technologies allow their identification, and a number of examples demonstrating that unintended effects are limited and diverse have recently been reported. Both from the food safety aspect and for research purposes, it is important to discern unintended changes produced by the transgene and its expression from those that may be attributed to other factors. Here, we show differential expression of around 0.40% transcriptome between conventional rice var. Senia and Senia-afp constitutively expressing the AFP antifungal protein. Analysis of one-fifth of the regulated sequences showed that around 35% of the unintended effects could be attributed to the process used to produce GM plants, based on in vitro tissue culture techniques. A further ∼15% were event specific, and their regulation was attributed to host gene disruption and genome rearrangements at the insertion site, and effects on proximal sequences. Thus, only around half the transcriptional unintended effects could be associated to the transgene itself. A significant number of changes in Senia-afp and Senia are part of the plant response to stress conditions, and around half the sequences for which up-regulation was attributed to the transgene were induced in conventional (but not transgenic) plants after wounding. Unintended effects might, as such, putatively result in widening the self-resistance characteristics because of the transgene in GM plants.

Proteomic analysis of MON810 and comparable non-GM maize varieties grown in agricultural fields.

Worldwide maize is the second major agricultural commodity and around one-fourth is currently biotech, with significant application of the insect resistant event MON810 particularly in the European Union. Grains are the major commercialized part of the plant, and can be harvested after maturity (for food and feed purposes) or at late milky-starchy stage (for forage uses, with the whole plant). We assessed possible proteomic unintended effects of the MON810 transgene using two-dimensional gel electrophoresis coupled to mass spectrometry. To keep in a realistic scenario we used plants grown in agricultural fields in a region where ~50% of maize was MON810, and analyzed grains at milky-starchy stage. In maize, differential transcripts and metabolites between GM and comparable non-GM varieties tend to be variety specific. Thus, we analyzed two variety pairs, DKC6575/Tietar and PR33P67/PR33P66 which are considered representative of Food and Agriculture Organization 700 and 600 varieties commercially grown in the region. MON810 and non-GM milky-starchy grains had virtually identical proteomic patterns, with a very small number of spots showing fold-variations in the 1-1.8 range. They were all variety specific and had divergent identities and functions. Although 2DE allows the analysis of a limited dataset our results support substantial equivalence between MON810 and comparable non-GM varieties.

Natural variation explains most transcriptomic changes among maize plants of MON810 and comparable non-GM varieties subjected to two N-fertilization farming practices.

The introduction of genetically modified organisms (GMO) in many countries follows strict regulations to ensure that only safety-tested products are marketed. Over the last few years, targeted approaches have been complemented by profiling methods to assess possible unintended effects of transformation. Here we used a commercial (Affymertix) microarray platform (i.e. allowing assessing the expression of approximately 1/3 of the genes of maize) to evaluate transcriptional differences between commercial MON810 GM maize and non-transgenic crops in real agricultural conditions, in a region where about 70% of the maize grown was MON810. To consider natural variation in gene expression in relation to biotech plants we took two common MON810/non-GM variety pairs as examples, and two farming practices (conventional and low-nitrogen fertilization). MON810 and comparable non-GM varieties grown in the field have very low numbers of sequences with differential expression, and their identity differs among varieties. Furthermore, we show that the differences between a given MON810 variety and the non-GM counterpart do not appear to depend to any major extent on the assayed cultural conditions, even though these differences may slightly vary between the conditions. In our study, natural variation explained most of the variability in gene expression among the samples. Up to 37.4% was dependent upon the variety (obtained by conventional breeding) and 31.9% a result of the fertilization treatment. In contrast, the MON810 GM character had a very minor effect (9.7%) on gene expression in the analyzed varieties and conditions, even though similar cryIA(b) expression levels were detected in the two MON810 varieties and nitrogen treatments. This indicates that transcriptional differences of conventionally-bred varieties and under different environmental conditions should be taken into account in safety assessment studies of GM plants.

Effect of volunteers on maize gene flow.

Regulatory approvals for deliberate release of GM maize events into the environment have lead to real situations of coexistence between GM and non-GM, with some fields being cultivated with GM and conventional varieties in successive seasons. Given the common presence of volunteer plants in maize fields in temperate areas, we investigated the real impact of GM volunteers on the yield of 12 non-GM agricultural fields. Volunteer density varied from residual to around 10% of plants in the field and was largely reduced using certain cultural practices. Plant vigour was low, they rarely had cobs and produced pollen that cross-fertilized neighbour plants only at low--but variable--levels. In the worst-case scenario, the estimated content of GMO was 0.16%. The influence of GM volunteers was not enough to reach the 0.9% adventitious GM threshold but it could potentially contribute to adventitious GM levels, especially at high initial densities (i.e. above 1,000 volunteers/ha).

Gene expression profiles of MON810 and comparable non-GM maize varieties cultured in the field are more similar than are those of conventional lines.

Maize is a major food crop and genetically modified (GM) varieties represented 24% of the global production in 2007. Authorized GM organisms have been tested for human and environmental safety. We previously used microarrays to compare the transcriptome profiles of widely used commercial MON810 versus near-isogenic varieties and reported differential expression of a small set of sequences in leaves of in vitro cultured plants of AristisBt/Aristis and PR33P67/PR33P66 (Coll et al. 2008). Here we further assessed the significance of these differential expression patterns in plants grown in a real context, i.e. in the field. Most sequences that were differentially expressed in plants cultured in vitro had the same expression values in MON810 and comparable varieties when grown in the field; and no sequence was found to be differentially regulated in the two variety pairs grown in the field. The differential expression patterns observed between in vitro and field culture were similar between MON810 and comparable varieties, with higher divergence between the two conventional varieties. This further indicates that MON810 and comparable non-GM varieties are equivalent except for the introduced character.

Multiplex polymerase chain reaction-capillary gel electrophoresis: a promising tool for GMO screening--assay for simultaneous detection of five genetically modified cotton events and species.

A multiplex polymerase chain reaction assay coupled to capillary gel electrophoresis for amplicon identification by size and color (multiplex PCR-CGE-SC) was developed for simultaneous detection of cotton species and 5 events of genetically modified (GM) cotton. Validated real-time-PCR reactions targeting Bollgard, Bollgard II, Roundup Ready, 3006-210-23, and 281-24-236 junction sequences, and the cotton reference gene acp1 were adapted to detect more than half of the European Union-approved individual or stacked GM cotton events in one reaction. The assay was fully specific (<1.7% of false classification rate), with limit of detection values of 0.1% for each event, which were also achieved with simulated mixtures at different relative percentages of targets. The assay was further combined with a second multiplex PCR-CGE-SC assay to allow simultaneous detection of 6 cotton and 5 maize targets (two endogenous genes and 9 GM events) in two multiplex PCRs and a single CGE, making the approach more economic. Besides allowing simultaneous detection of many targets with adequate specificity and sensitivity, the multiplex PCR-CGE-SC approach has high throughput and automation capabilities, while keeping a very simple protocol, e.g., amplification and labeling in one step. Thus, it is an easy and inexpensive tool for initial screening, to be complemented with quantitative assays if necessary.

[Weight, dietary patterns and exercise habits in first-year primary school children: the AVall study]. / Estado ponderal, hábitos alimentarios y de actividad física en escolares de primer curso de educación primaria: estudio AVall.

OBJECTIVE: To evaluate weight, dietary patterns and exercise habits in children attending the first year of primary school in the city of Granollers (Spain). METHODS: We performed a cross-sectional study of children enrolled in the schools of the city of Granollers. All the children were born in 2000. Data were collected from September to October 2006. Weight and height were measured in each schoolchild. The parents completed a questionnaire on the frequency of food intake and physical activity and the Krece Plus test. The International Obesity Task Force cut-offs for body mass index were used to define overweight and obesity. RESULTS: A total of 566 schoolchildren were included. The prevalence of overweight was 19.6% and that of obesity was 8.5%. Only 3.8% of the children had an adequate breakfast and 17.1% ate five portions of fruit and vegetables a day. Some families consumed a low amount of fruit (22%), vegetables (37%), bread/pasta/ rice/cereals (14%), fish (32%), legumes (13%) and nuts (9%). Children who had lunch at school ate more fruits (38% vs 29%), vegetables (35% vs 25%) and fish (82% vs 73%) than those who did not have lunch at school. A total of 82% of the schoolchildren exercised regularly. CONCLUSIONS: A quarter of the children who participated in the study were overweight. The schoolchildren who had lunch at school had better dietary patterns. Inappropriate family habits can determine children's dietary habits.

Use of omics analytical methods in the study of genetically modified maize varieties tested in 90 days feeding trials.

Genetically modified (GM) maize and their non-modified counterparts were compared using MON810 varieties, the only GMO event cultivated in Europe. The differences in grain samples were analysed by omics profiles, including transcriptomics, proteomics and metabolomics. Other cultivated maize varieties were analysed as a reference for the variability that will exist between cultivated varieties. The observed differences between modified and non-modified maize varieties do not exceed typical differences between non-modified varieties. The use of these advanced analytical approaches to analyse novel plant materials as compared to the results from animal feeding trials with whole foods is assessed. No indications were observed for changes in the GM varieties that warrant further investigations. Furthermore, it was shown that such indications will be obtained if maize samples of inferior quality are analysed similarly. Omics data provide detailed analytical information of the plant material, which facilitates a risk assessment procedure of new (GM) plant varieties.

Impact of school-based nutrition and physical activity intervention on body mass index eight years after cessation of randomized controlled trial (AVall study).

BACKGROUND & AIMS: The prevalence of obesity and overweight among children is increasing, representing a new and pressing societal problem. Excess weight in childhood is an independent risk factor for adult obesity. Although school-based interventions are generally considered effective in the short term, few studies analyze their longterm impact. The aim of study was to assess if the effect of the intervention on body mass Index (BMI) immediately after the intervention remained eight years later (AVall Study). METHODS: In 2006-2008, an intervention for primary school children promoted healthy eating habits and physical activity in the school setting using the Investigation, Vision, Action and Change (IVAC) educational methodology, which involves children as active participants in healthy change. At baseline, parents reported their weight, height and educational level by questionnaire. Children's weight and height were measured in situ in 2006, 2008, 2010, 2012 and 2016, and levels of physical activity were assessed by questionnaire. Multilevel mixed effects linear regression was used to assess changes in BMI over time. RESULTS: Increases in BMI from 2006 to 2016 were 0.68 kg/m2 (95% CI, 0.02, 1.34; P = 0.045) higher in the control group than in the intervention group. The prevalence of obesity and overweight combined in 2006 and 2016 was 22.2% and 27.9%, respectively, in the control group and 25.6% and 21.2% respectively, in the intervention group. Changes in BMI in the intervention group were maintained from 2006 on: at the end of the intervention in 2008, -0.4 kg/m2 (P = 0.001); in 2010, -0.23 g/m2 (P = 0.012); in 2012, -0.63 kg/m2 (P < 0.001) and in 2016, -0.27 kg/m2 (P = 0.025). The child's BMI increased by 0.52 kg/m2 (P = 0.046) if the father was obese, by 1.26 kg/m2 (p = 0.011) if the mother was obese, and by 2.37 kg/m2 (P < 0.001) if both parents were obese. Parental education levels were not associated with childhood obesity. CONCLUSIONS: A school-based healthy eating habits and physical activity intervention using IVAC methodology contributed to lower increases in BMI among children in primary school. Although parental BMI also influenced children's BMI, the intervention was effective. TRIAL REGISTRATION: ClinicalTrials.gov NCT01156805.

Novel Rosaceae plant elicitor peptides as sustainable tools to control Xanthomonas arboricola pv. pruni in Prunus spp.

Fruit crops are regarded as important health promoters and constitute a major part of global agricultural production, and Rosaceae species are of high economic impact. Their culture is threatened by bacterial diseases, whose control is based on preventative treatments using compounds of limited efficacy and negative environmental impact. One of the most economically relevant examples is the pathogen Xanthomonas arboricola pv. pruni (Xap) affecting Prunus spp. The plant immune response against pathogens can be triggered and amplified by plant elicitor peptides (Peps), perceived by specific receptors (PEPRs). Although they have been described in various angiosperms, scarce information is available on Rosaceae species. Here, we identified the Pep precursor (PROPEP), Pep and PEPR orthologues of 10 Rosaceae species and confirmed the presence of the Pep/PEPR system in this family. We showed the perception and elicitor activity of Rosaceae Peps using the Prunus-Xap pathosystem as proof-of-concept. Treatment with nanomolar doses of Peps induced the corresponding PROPEP and a set of defence-related genes in Prunus leaves, and enhanced resistance against Xap. Peps from the same species had the highest efficiencies. Rosaceae Peps could potentially be used to develop natural, targeted and environmentally friendly strategies to enhance the resistance of Prunus species against biotic attackers.